Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Sport Touring: ST4 / ST3 / ST2 > Volatge regulator?

[rockhopper]

Went for a ride to Waddington airshow today. Bike didnt feel quite right on the way there. Cant put my finger on it but it didnt feel as perky as normal. On the way home it was missing and didnt want to rev. i turned the lights off and that helped for a few miles but we eventually had to pull into a layby on the A14. The batter was totally dead so i'm guessing it was the voltage regulator that has gone?

I tried a search on here for previous postings about this but i think i'm using it wrong cos nothing came up.

Any ideas how much a new one might be or how to test the one ive got bearing in mind that the bike wont run till i get the battery charged up. I seem to remember someone saying that a honda part will fit and is a bit cheaper?

The bike is a 1999 ST4 by the way.

Oh and to the six or seven dukes that passed us in the layby while we were waiting for the recovery truck, thanks so much for not even nodding to us. At least two passed the bike while i had gone into a field to use the phone ( it was quieter) leaving my mrs with all our kit spread out and the seat off. Only one bike ( i think it was a Kawasaki) waved and gave the thumbs up to see if we were okay.

Paul.

[nelly]

Sorry to hear about the problem Paul.
Checking is pretty easy. Once the battery is re-charged, start the bike and measure the voltage across the battery terminals. Should be 14.4v or there abouts, at 2-3000 revs.
The OE ones aren't cheap, about £140 ish.
There are pattern ones about for about £60-£70. They need a bit of a wiring job though.
You know where I am if you need a hand

[KeefyB]

Paul,
First recharge your battery and fit it on the bike.You will need a multimeter to test the charging voltage.You can get them in most car accesory shops for 10-20 quid.With the bike started you should get about 14.5v dc across the battery terminals.If the charging seems ok,have a look at the fuel filter,its amazing how a blocked filter can put a strain on the electrics.
A new reg/rec should cost in the region of 120 quid.The Honda ones mentioned were for the older two phase alternators.I guess your bike will be a three phase.If you need a cheaper reg/rec then look at a Newtronics or Electrex item.
Hehehe,....nelly beat me to it.

[Edited on 29-6-2003 by keefyboy]

[Rushjob]

Ooooh!
I've just been through the dreaded regulator problem, just ask the mob who had to bump start me at the last Notts DSC meet.
Cornerspeed had a geniune one ( the heavily finned 748 / 916 type ) at a cracking price andas a precaution,when installing it I have relocated the reg from below the headlight to actually inside the front air intake to give some airflow to allow it to run a little cooler- as I have an open air box I'm not worried about restricting airflow through there.
Fingers crossed...
Andy

[Iconic944ss]

Sorry to hear of your probs....Buster accessories have lots of Duke regulators mentioned on their website for £60 but sadly, not yours specifically.

Dont know how good they are or if they need mods...here is a link anyways (look in the spares section)

http://www.busters-accessories.co.uk/

If it is the regulator try taking your old part to an electrical motor factors (locally I used a firm called Diesel auto electrics who are excellent and sourced me a new started relay for £10 !!!)

Good luck

[rockhopper]

Thanks for all the info guys, it helps to restore my faith in bikers!

Well tonight i took all the plastic off and put the battery on charge. I spotted thet the connector on the right hand side of the bike by the coolant header tank has suffered a small fire! I recall reading that this can happen but cant remember what casues it. It might have been casued by a failed regulator or have taken out the regulator as a result. Guess i wont know till i've repaired it and got the battery charged. I really cant afford a new reg at the moment but i cant be without the bike now that the summer is here!

Fingers crossed and thanks once again for all the support and info.


Paul

[rockhopper]

I guess the picture idea didnt work!

[Shazaam!]

The main problem with Ducati charging systems is that the stator wires are way undersized and the in-line connectors develop a high resistance, heat-up and melt.

The rule-of-thumb for sizing wiring is that if it needs to carry 20 amps use 12 gauge wire; 30 amps needs 10 gauge; 40 amps needs #8 gauge. Early bikes have 350 watt/29 amp two-wire charging systems so 10 gauge should be used. Newer three-wire 500 watt alternators can produce a little over 40 amps. So you ought to replace the wiring all the way back to the stator with 8 gauge wire.

These wires have to pass 30 amps or more continuously. There’s an electrical phenomenon called I-squared-R loss. That is, if you run 30 amps through a corroded or loose connector having (say) a 1/2-ohm resistance, the heating effect is 30 X 30 X 1/2, or 450 watts. That’s a lot of continuous heat. This heat just conducts down the wire, cooking the insulation as it goes.

Just like you can’t put your hand on a 450 watt light bulb while it’s lit, you can’t expect a plastic connector to survive radiating 450 watts of power either. A corroded or loose connector always has a higher resistance than the adjacent wires and it will heat up enough to melt connector plastic parts and nearby wire insulation. That’s why it’s best to solder the wires directly together and eliminate connectors entirely.

It is the connectors heating up that causing the insulation and conductors to melt and short out. Even if you haven't had a charging failure, next time you have a chance, check your wiring for damage.



On my 916, the stator wires got so hot that the insulation became brittle and cracked near the regulator connectors. A closer examination showed that the damage extended along the wire all the way back to the engine casing. I could scrape off the softened insulation with my fingernail. Rewire it.

[KeefyB]

Paul,
Your reg/rec is probably ok.As Shazaam says,rewire the burnt bit of wiring and use new heavier duty connectors.Charge your battery and test the charge voltage.You can get auto electric wiring materials from good car accessory shops or there is a place not far from you,Merv Plastics(?),they used to advertise in the bike mags.
They have changed their name,
www.vehicle-wiring-products.co.uk

[Edited on 30-6-2003 by keefyboy]

[rockhopper]

Well i finished putting it back together at 9.30 last night. I replaced the burnt out connector and the next one in line with some 40 amp wire i had lying around, soldered the joints and covered it all with heat shrink. Start her up and its all working fine! The only trouble is that I've now lost a little of my confidence in the bike although having said that its the first time i've had to use the recovery thing in the last four years.

Guys, thanks once again for everyones help. Hopefully see some of you at the Unicorn in the not too distant future.

Paul.


( i see the picture decided to display its self, it wasnt working last night)